Qt Documentation

Qt 5.8
Qt Graphical Effects
QML Types
InnerShadow QML Type

InnerShadow QML Type

Generates a colorized and blurred shadow inside the source. More...

Import Statement:	import QtGraphicalEffects 1.0
Since:	QtGraphicalEffects 1.0
Inherits:	Item

List of all members, including inherited members

Properties

cached : bool
color : color
fast : bool
horizontalOffset : real
radius : real
samples : int
source : variant
spread : real
verticalOffset : real

Detailed Description

By default the effect produces a high quality shadow image, thus the rendering speed of the shadow might not be the highest possible. The rendering speed is reduced especially if the shadow edges are heavily softened. For use cases that require faster rendering speed and for which the highest possible visual quality is not necessary, property fast can be set to true.

Source	Effect applied

Note: This effect is available when running with OpenGL.

Example

The following example shows how to apply the effect.

import QtQuick 2.0
import QtGraphicalEffects 1.0

Item {
    width: 300
    height: 300

    Rectangle {
        anchors.fill: parent
    }

    Image {
        id: butterfly
        source: "images/butterfly.png"
        sourceSize: Qt.size(parent.width, parent.height)
        smooth: true
        visible: false
    }

    InnerShadow {
        anchors.fill: butterfly
        radius: 8.0
        samples: 16
        horizontalOffset: -3
        verticalOffset: 3
        color: "#b0000000"
        source: butterfly
    }
}

Property Documentation

cached : bool

This property allows the effect output pixels to be cached in order to improve the rendering performance. Every time the source or effect properties are changed, the pixels in the cache must be updated. Memory consumption is increased, because an extra buffer of memory is required for storing the effect output.

It is recommended to disable the cache when the source or the effect properties are animated.

By default, the property is set to false.

color : color

This property defines the RGBA color value which is used for the shadow.

By default, the property is set to "black".

Output examples with different color values

color: #000000	color: #ffffff	color: #ff0000
radius: 16	radius: 16	radius: 16
samples: 24	samples: 24	samples: 24
horizontalOffset: 0	horizontalOffset: 0	horizontalOffset: 0
verticalOffset: 0	verticalOffset: 0	verticalOffset: 0
spread: 0.2	spread: 0.2	spread: 0.2

fast : bool

This property selects the blurring algorithm that is used to produce the softness for the effect. Setting this to true enables fast algorithm, setting value to false produces higher quality result.

By default, the property is set to false.

Output examples with different fast values

fast: false	fast: true
radius: 16	radius: 16
samples: 24	samples: 24
color: #000000	color: #000000
horizontalOffset: 0	horizontalOffset: 0
verticalOffset: 0	verticalOffset: 0
spread: 0.2	spread: 0.2

horizontalOffset : real

HorizontalOffset and verticalOffset properties define the offset for the rendered shadow compared to the InnerShadow item position. Often, the InnerShadow item is anchored so that it fills the source element. In this case, if the HorizontalOffset and verticalOffset properties are set to 0, the shadow is rendered fully inside the source item. By changing the offset properties, the shadow can be positioned relatively to the source item.

The values range from -inf to inf. By default, the properties are set to 0.

Output examples with different horizontalOffset values

horizontalOffset: -20	horizontalOffset: 0	horizontalOffset: 20
radius: 16	radius: 16	radius: 16
samples: 24	samples: 24	samples: 24
color: #000000	color: #000000	color: #000000
verticalOffset: 0	verticalOffset: 0	verticalOffset: 0
spread: 0	spread: 0	spread: 0

radius : real

Radius defines the softness of the shadow. A larger radius causes the edges of the shadow to appear more blurry.

Depending on the radius value, value of the samples should be set to sufficiently large to ensure the visual quality.

The value ranges from 0.0 (no blur) to inf. By default, the property is set to 0.0 (no blur).

Output examples with different radius values

radius: 0	radius: 6	radius: 12
samples: 24	samples: 24	samples: 24
color: #000000	color: #000000	color: #000000
horizontalOffset: 0	horizontalOffset: 0	horizontalOffset: 0
verticalOffset: 0	verticalOffset: 0	verticalOffset: 0
spread: 0	spread: 0	spread: 0

samples : int

This property defines how many samples are taken per pixel when edge softening blur calculation is done. Larger value produces better quality, but is slower to render.

Ideally, this value should be twice as large as the highest required radius value, for example, if the radius is animated between 0.0 and 4.0, samples should be set to 8.

The value ranges from 0 to 32. By default, the property is set to 0.

This property is not intended to be animated. Changing this property may cause the underlying OpenGL shaders to be recompiled.

When fast property is set to true, this property has no effect.

source : variant

This property defines the source item that is going to be used as the source for the generated shadow.

Note: It is not supported to let the effect include itself, for instance by setting source to the effect's parent.

spread : real

This property defines how large part of the shadow color is strenghtened near the source edges.

The value ranges from 0.0 to 1.0. By default, the property is set to 0.5.

Output examples with different spread values

spread: 0.0	spread: 0.3	spread: 0.5
radius: 16	radius: 16	radius: 16
samples: 24	samples: 24	samples: 24
color: #000000	color: #000000	color: #000000
horizontalOffset: 0	horizontalOffset: 0	horizontalOffset: 0
verticalOffset: 0	verticalOffset: 0	verticalOffset: 0

verticalOffset : real